<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8" />
    <title>Hello React!</title>
    <script src="https://cdn.staticfile.org/react/16.4.0/umd/react.development.js"></script>
    <script src="https://cdn.staticfile.org/react-dom/16.4.0/umd/react-dom.development.js"></script>
    <script src="https://cdn.staticfile.org/babel-standalone/6.26.0/babel.min.js"></script>
</head>
<body>

<div id="example"></div>
<script type="text/babel">
    {/*注意，原生 HTML 元素名以小写字母开头，而自定义的 React 类名以大写字母开头，
    比如 HelloMessage 不能写成 helloMessage。除此之外还需要注意组件类只能包含一个顶层标签，否则也会报错。*/}
    function Clock(props) {
        return (
        <div>
        <h1>Hello, world!</h1>
        <h2>现在是 {props.date.toLocaleTimeString()}.</h2>
        </div>
    );
    }

    function tick() {
        ReactDOM.render(
        <Clock date={new Date()} />,
                document.getElementById('example')
    );
    }

    setInterval(tick, 1000);
</script>

</body>
</html>